Being the faithful servant to the Surface Pro creative community that I am, I investigated and found that enabling canvas rotation does indeed make the software unusable.

There's a GetSatisfaction thread on the issue here with some workarounds that involve rolling back the updates.

No official word from Autodesk yet, but we'll stay tuned.

In the meantime, anyone know how to adjust Sketchbook Pro's preferences without loading the software?

UPDATE: Found a workaround for getting the software to load again. Inside your UserName\AppData\Roaming\Autodesk\SketchBook Pro directory is a file name userPreferences.xml. Delete this file and Sketchbook Pro will load in its factory state. Now don't touch that Enable Canvas Rotation setting!

I'll update this post as more information becomes available.

UPDATE 2: Fate Dreamer on GetSatisfaction wrote: "You can open the xml file and modify the value for the option. Search for Rotate Desktop Canvas (Or canvas, it's the first one) and set it to false. Works like a charm and you don't lose other settings." Duh. Thanks!